/*
 * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.nulldev.util.graphics.renderIt.ginterfaces.marlin.impl.pisces;

import static com.nulldev.util.graphics.renderIt.ginterfaces.marlin.impl.pisces.ArrayCacheConst.ARRAY_SIZES;
import static com.nulldev.util.graphics.renderIt.ginterfaces.marlin.impl.pisces.ArrayCacheConst.BUCKETS;
import static com.nulldev.util.graphics.renderIt.ginterfaces.marlin.impl.pisces.ArrayCacheConst.MAX_ARRAY_SIZE;
import static com.nulldev.util.graphics.renderIt.ginterfaces.marlin.impl.pisces.MarlinUtils.logException;
import static com.nulldev.util.graphics.renderIt.ginterfaces.marlin.impl.pisces.MarlinUtils.logInfo;

import java.lang.ref.WeakReference;
import java.util.Arrays;

import com.nulldev.util.graphics.renderIt.ginterfaces.marlin.impl.pisces.ArrayCacheConst.BucketStats;
import com.nulldev.util.graphics.renderIt.ginterfaces.marlin.impl.pisces.ArrayCacheConst.CacheStats;

/*
 * Note that the [BYTE/INT/FLOAT/DOUBLE]ArrayCache files are nearly identical except
 * for a few type and name differences. Typically, the [BYTE]ArrayCache.java file
 * is edited manually and then [INT/FLOAT/DOUBLE]ArrayCache.java
 * files are generated with the following command lines:
 */
// % sed -e 's/(b\yte)[ ]*//g' -e 's/b\yte/int/g' -e 's/B\yte/Int/g' < B\yteArrayCache.java > IntArrayCache.java
// % sed -e 's/(b\yte)[ ]*0/0.0f/g' -e 's/(b\yte)[ ]*/(float) /g' -e 's/b\yte/float/g' -e 's/B\yte/Float/g' < B\yteArrayCache.java > FloatArrayCache.java
// % sed -e 's/(b\yte)[ ]*0/0.0d/g' -e 's/(b\yte)[ ]*/(double) /g' -e 's/b\yte/double/g' -e 's/B\yte/Double/g' < B\yteArrayCache.java > DoubleArrayCache.java

final class IntArrayCache implements MarlinConst {

	final boolean clean;
	private final int bucketCapacity;
	private WeakReference<Bucket[]> refBuckets = null;
	final CacheStats stats;

	IntArrayCache(final boolean clean, final int bucketCapacity) {
		this.clean = clean;
		this.bucketCapacity = bucketCapacity;
		this.stats = (DO_STATS) ? new CacheStats(getLogPrefix(clean) + "IntArrayCache") : null;
	}

	Bucket getCacheBucket(final int length) {
		final int bucket = ArrayCacheConst.getBucket(length);
		return getBuckets()[bucket];
	}

	private Bucket[] getBuckets() {
		// resolve reference:
		Bucket[] buckets = (refBuckets != null) ? refBuckets.get() : null;

		// create a new buckets ?
		if (buckets == null) {
			buckets = new Bucket[BUCKETS];

			for (int i = 0; i < BUCKETS; i++) {
				buckets[i] = new Bucket(clean, ARRAY_SIZES[i], bucketCapacity, (DO_STATS) ? stats.bucketStats[i] : null);
			}

			// update weak reference:
			refBuckets = new WeakReference<Bucket[]>(buckets);
		}
		return buckets;
	}

	Reference createRef(final int initialSize) {
		return new Reference(this, initialSize);
	}

	static final class Reference {

		// initial array reference (direct access)
		final int[] initial;
		private final boolean clean;
		private final IntArrayCache cache;

		Reference(final IntArrayCache cache, final int initialSize) {
			this.cache = cache;
			this.clean = cache.clean;
			this.initial = createArray(initialSize);
			if (DO_STATS) {
				cache.stats.totalInitial += initialSize;
			}
		}

		int[] getArray(final int length) {
			if (length <= MAX_ARRAY_SIZE) {
				return cache.getCacheBucket(length).getArray();
			}
			if (DO_STATS) {
				cache.stats.oversize++;
			}
			if (DO_LOG_OVERSIZE) {
				logInfo(getLogPrefix(clean) + "IntArrayCache: " + "getArray[oversize]: length=\t" + length);
			}
			return createArray(length);
		}

		int[] widenArray(final int[] array, final int usedSize, final int needSize) {
			final int length = array.length;
			if (DO_CHECKS && length >= needSize) {
				return array;
			}
			if (DO_STATS) {
				cache.stats.resize++;
			}

			// maybe change bucket:
			// ensure getNewSize() > newSize:
			final int[] res = getArray(ArrayCacheConst.getNewSize(usedSize, needSize));

			// use wrapper to ensure proper copy:
			System.arraycopy(array, 0, res, 0, usedSize); // copy only used elements

			// maybe return current array:
			putArray(array, 0, usedSize); // ensure array is cleared

			if (DO_LOG_WIDEN_ARRAY) {
				logInfo(getLogPrefix(clean) + "IntArrayCache: " + "widenArray[" + res.length + "]: usedSize=\t" + usedSize + "\tlength=\t" + length
						+ "\tneeded length=\t" + needSize);
			}
			return res;
		}

		int[] putArray(final int[] array) {
			// dirty array helper:
			return putArray(array, 0, array.length);
		}

		int[] putArray(final int[] array, final int fromIndex, final int toIndex) {
			if (array.length <= MAX_ARRAY_SIZE) {
				if ((clean || DO_CLEAN_DIRTY) && (toIndex != 0)) {
					// clean-up array of dirty part[fromIndex; toIndex[
					fill(array, fromIndex, toIndex, 0);
				}
				// ensure to never store initial arrays in cache:
				if (array != initial) {
					cache.getCacheBucket(array.length).putArray(array);
				}
			}
			return initial;
		}
	}

	static final class Bucket {

		private int tail = 0;
		private final int arraySize;
		private final boolean clean;
		private final int[][] arrays;
		private final BucketStats stats;

		Bucket(final boolean clean, final int arraySize, final int capacity, final BucketStats stats) {
			this.arraySize = arraySize;
			this.clean = clean;
			this.stats = stats;
			this.arrays = new int[capacity][];
		}

		int[] getArray() {
			if (DO_STATS) {
				stats.getOp++;
			}
			// use cache:
			if (tail != 0) {
				final int[] array = arrays[--tail];
				arrays[tail] = null;
				return array;
			}
			if (DO_STATS) {
				stats.createOp++;
			}
			return createArray(arraySize);
		}

		void putArray(final int[] array) {
			if (DO_CHECKS && (array.length != arraySize)) {
				logInfo(getLogPrefix(clean) + "IntArrayCache: " + "bad length = " + array.length);
				return;
			}
			if (DO_STATS) {
				stats.returnOp++;
			}
			// fill cache:
			if (arrays.length > tail) {
				arrays[tail++] = array;

				if (DO_STATS) {
					stats.updateMaxSize(tail);
				}
			} else if (DO_CHECKS) {
				logInfo(getLogPrefix(clean) + "IntArrayCache: " + "array capacity exceeded !");
			}
		}
	}

	static int[] createArray(final int length) {
		return new int[length];
	}

	static void fill(final int[] array, final int fromIndex, final int toIndex, final int value) {
		// clear array data:
		Arrays.fill(array, fromIndex, toIndex, value);
		if (DO_CHECKS) {
			check(array, fromIndex, toIndex, value);
		}
	}

	static void check(final int[] array, final int fromIndex, final int toIndex, final int value) {
		if (DO_CHECKS) {
			// check zero on full array:
			for (int i = 0; i < array.length; i++) {
				if (array[i] != value) {
					logException("Invalid value at: " + i + " = " + array[i] + " from: " + fromIndex + " to: " + toIndex + "\n" + Arrays.toString(array),
							new Throwable());

					// ensure array is correctly filled:
					Arrays.fill(array, value);

					return;
				}
			}
		}
	}

	static String getLogPrefix(final boolean clean) {
		return (clean) ? "Clean" : "Dirty";
	}
}
